Maricopa County Sheriff Joe Arpaio announced the controversial plan in the wake of the December Newtown, Conn., school shooting that left 27 people dead, including the gunman and 20 first-graders.

The exercise is planned for Saturday at a closed school site in suburban Fountain Hills outside Phoenix where sheriff's SWAT members will act as shooters and 25 teenagers will play the part of students during mock scenarios involving up to three gunmen.

Seagal, best known for his roles in movies such as "Above the Law" and "Under Siege," will lead training on hand-to-hand defense tactics, among other techniques, drawing from his expertise in martial arts, according to a sheriff's office news release.

Arpaio's office didn't respond to requests for comment Friday, and Seagal representatives also did not return telephone messages from The Associated Press.

When faced with criticism in January about the school posse plan, Arpaio snapped back: "Why would people complain about my posse being in front of schools to act as prevention?"

He boldly announced the plan on the grounds of an elementary school, saying at the time he wanted the patrols publicized.

"I want everyone to know about it for the deterrence effect," Arpaio said, adding that no taxpayer money would be spent on the patrols and volunteers will be supervised over the radio or telephone by actual deputies.

Arizona Democratic House Minority Leader Chad Campbell called the plan to use Seagal as an instructor "ludicrous."

"Steve Seagal is an actor. That's it. Why don't we also have Clint Eastwood and Chuck Norris and Bruce Willis come out and train them too while we're at it," Campbell said.

Campbell has been a vocal critic of Arpaio's school posse protection plan, complaining that using untrained, armed civilians to protect students is a bad idea and likely will only make the facilities more dangerous.

"He's making a mockery out of it. You're having a movie actor train people how to protect schools?" Campbell said.

Randy Parraz, president of Citizens for a Better Arizona, also a longtime Arpaio critic, said it's unfortunate the sheriff, known nationally for his tough stance on illegal immigration, is using the "wake of a tragedy like Newtown" to grab headlines.

"We'd like to think he would take something like this much more seriously," said Parraz, who added that his group planned to be at Saturday's event with petitions to recall Arpaio.

The patrols were launched at 59 schools in January throughout unincorporated areas and communities that pay Arpaio's agency for police services. The sheriff announced this week he needs more members to continue the patrols, calling for 1,000 additional citizens to step up and volunteer.

Current posse members already are used to bolster the sheriff's office force by providing police protection at malls during the holidays, directing traffic and transporting people to jail.

Arpaio even sent one group of posse members to Hawaii to conduct an examination into the authenticity of President Barack Obama's birth certificate.

Joselyn Wells, a mother of three children at a school in suburban Phoenix, where Arpaio's posse has begun patrolling, said she was excited to hear about the initiative.

"A lot of people sit around and watch these things happen, watch key signs and no one wants to do anything about it," she said when Arpaio announced the plan. "Nobody wants conflict, nobody wants to be out in the limelight. And he doesn't care. He wants to do the right thing."

Andrew Sanchez, however, a town council member in Guadalupe, said he wants nothing to do with posse members patrolling schools in his community, which spends about $1.2 million annually for Maricopa County sheriff's patrols.

"We are paying him to have certified deputies here, not to bring a circus and not to use our town as a political platform," Sanchez has said.

The volunteers, dressed in uniforms and driving patrol vehicles, some authorized to carry guns after training, won't go onto school grounds unless they spot danger, but will instead patrol around the facilities, Arpaio said.

Seagal is already a volunteer posse member in Maricopa County, and has been deputized with sheriff's offices in New Mexico, Texas and Louisiana, where a film crew followed the actor on ride-alongs with Jefferson Parish sheriff's deputies for the reality TV show "Steven Seagal: Lawman."

Arpaio says other notable people also have joined his more than 3,000-strong volunteer armed posse, including "The Incredible Hulk" star Lou Ferrigno and actor Peter Lupus of TV's "Mission: Impossible."